The invention relates to a longitudinally guiding driver assistance system in a motor vehicle.
In principle, many longitudinally guiding driver assistance systems, which are in the form of speed regulation systems and regulate the speed of the motor vehicle to a predefined desired or maximum permissible maximum speed, are already known. In addition to these longitudinal regulation systems, longitudinal regulation systems enhanced with distance regulation, so-called distance-based longitudinal regulation systems, or speed regulation systems, can also nowadays already be purchased from some manufacturers. Such systems offered (for example by the Applicant of the present patent application under the name “active cruise control”) make it possible to automatically guide the motor vehicle at a desired or accordingly lower speed while complying with a desired distance from a vehicle traveling in front. If a distance sensor system, which is fitted to the motor vehicle and can operate, in particular, on a radar basis, detects a target object or (motor) vehicle traveling in front in its own lane, its own speed is adapted (for example by causing a suitable braking torque) to the speed of the motor vehicle traveling in front or of the target object such that distance regulation included in the “active travel speed regulation” or in the corresponding longitudinal regulation system automatically adjusts and complies with a distance from the motor vehicle or target object traveling in front which is appropriate to the situation.
Longitudinally guiding driver assistance systems which are in the form of so-called speed restriction systems and prevent the maximum permissible speed set by the driver from being exceeded are also known.
DE 10 2012 211 967 A1 describes a combination of a speed restriction system and a speed regulation system, the maximum permissible maximum speed of the speed restriction system being able to be adopted, instead of the selected set speed, as the (new) desired or target speed for the speed regulation.
Finally, recent vehicles also contain driver assistance systems which predictively identify a speed restriction either from map data from a navigation system and/or by use of image processing and can pennanently display this to the driver after reaching the speed restriction. The result is that the driver can independently adapt his speed to the speed restriction if necessary (for example, BMW Speed Limit Info).
DE 10 2008 018 421 A1 discloses a driver assistance system for transmitting and receiving speed data and/or traffic density data for controlling a speed regulation system which determines a maximum permissible maximum speed on the basis of the received data and communicates this to the driver by outputting a corresponding notification. The driver can adopt this specification of the permissible speed for his speed regulation system by means of simple actuation.
DE 102014215673 A1, which is still unpublished, likewise discloses a longitudinally guiding driver assistance system which determines a deceleration strategy, if an upcoming event which requires a speed reduction is identified, and, at a defined time before reaching the event, outputs a request notification to the driver for permitting the automatic implementation of the deceleration strategy. If the driver actuates the request notification, automatic implementation of the deceleration strategy is initiated. In this case, the identification unit can determine or identify a relevant event either on the basis of map data (for example from a navigation device) or on the basis of camera data.
The object of the invention is to provide an improved longitudinally guiding driver assistance system which outputs a predictive notification of a change in the maximum permissible maximum speed in a manner which can be understood by the driver.
This and other objects are achieved by a driver assistance system according to the invention for a motor vehicle comprising a map-based detection system for identifying upcoming events which result in a change in the maximum permissible maximum speed, and a functional unit which, if a relevant upcoming event is identified by the map-based detection system, causes output of a request notification to permit an automatic adjustment of the currently maximum permissible maximum speed to a new maximum permissible maximum speed at a defined time before the upcoming event is reached. If a (manually) triggered permission confirmation (for example by actuating an operating element) is identified, an automatic adjustment of the currently maximum permissible maximum speed to a (determined) new maximum permissible maximum speed is carried out.
The upcoming events may be, for example, temporary or permanent speed restrictions which are either directly indicated on a traffic sign or can be derived therefrom on the basis of the general traffic rules (for example, there is a speed restriction to 50 km/h when passing through a town in Germany). The event may likewise also be an event which eliminates a speed restriction or at least an event which causes an increase to a new maximum speed, as is usually the case when leaving a town, for example.
The (new) maximum permissible maximum speed which is relevant to the longitudinally guiding speed system at the location of the upcoming event can be either the actually predefined new speed restriction or a speed which differs upward or downward from the predefined new speed restriction by a predefined amount, in which case the amount and direction of the difference can also be set by the driver in a central vehicle menu, for example. This new maximum speed can be directly transmitted to the functional unit or it can be determined on the basis of the available information in the functional unit.
Alternatively or additionally, it is also possible for the driver himself to stipulate speed limits in a location-based manner on a route known to him using an interface inside or outside the vehicle. When driving along the route with an active longitudinal guidance system, these speed limits can be accordingly taken into account as new maximum speeds. In this case, the driver can also select in advance, for example, whether he fundamentally wishes to have all speed limits stipulated by himself taken into account or only speed limits selected according to a rule, for example only on a particular route, for particular road classes, at a particular time, depending on weather conditions, etc. It is also possible to create a plurality of speed profiles for a particular route section which are then active according to predefined rules (speed profile for good road conditions, speed profile for wet roads and/or speed profile for snow-covered roads).
The term “time” can be understood as meaning a local time, the reaching of which causes the output of the request notification.
The functional unit is also set up to cause withdrawal of the output of the request notification if permission confirmation is identified. The output of the request notification is likewise withdrawn if a (manually) triggered rejection of the request notification is identified.
The invention is based on the following knowledge. If the upcoming event which results in a change in the maximum permissible maximum speed is identified by means of a map-based detection system, that is to say the location of the relevant event is determined from the map data used, a situation may occur, on the basis of the map data used, in which the location of the relevant event stored in the map data does not match the actual location of this event. In the map data conventionally used nowadays, the location of the upcoming event is generally stored before the actual location of the relevant event. Furthermore, speed-restricting events which are not in the actual course of the road (any longer) may be stored in the map data.
In order to prevent an upcoming event which is identified using a map-based detection system and results in a change in the maximum permissible maximum speed from being permanently displayed, provision is fundamentally made for the output of the request notification to be withdrawn at some point even if permission confirmation is not identified or rejection is not identified. However, since the relevant location determined on the basis of the map data is often before the actual location of the relevant event, a situation might occur, if the display of the request notification is withdrawn too early, in which, if the upcoming speed limit is perceived by the driver only shortly before the actual location and the permission to automatically change the maximum permissible maximum speed only then wishes to be confirmed, this is no longer possible under certain circumstances, the map-based location has already been passed and the output of the request notification has already been withdrawn. This might result in a misunderstanding by the driver.
In order to prevent such a situation, the invention also provides for the functional unit to be set up to cause withdrawal of the output of the request notification, and therefore also withdrawal of the possibility to permit the automatic adjustment of the maximum permitted maximum speed, only after the identified relevant event has happened, that is to say only after the location of the relevant upcoming event, as determined from the map data, if permission confirmation is not identified and if rejection is not identified.
For this purpose, the functional unit is advantageously set up, if permission confirmation is not identified and if rejection is not identified, to cause withdrawal of the display of the request notification at the earliest when the location of the relevant event determined on the basis of the map data has been reached and a time or distance interval which begins with the reaching of this location has additionally passed. A time interval can be understood as meaning a period, and a distance interval can be understood as meaning a route length, in which case a combination of a time interval and a distance interval is also contemplated. The (respective) time and/or distance interval can be advantageously predefined on the basis of predefined parameters, for example the speed. The time or distance interval may likewise also be composed of a constant interval portion and a speed-dependent interval portion in order to thus enable an optimum period for displaying the request signal if a permission signal is not confirmed.
If the longitudinally guiding driver assistance system includes a further detection system which can identify upcoming events which result in a change in the maximum permissible maximum speed on the basis of camera-based data, the functional unit may be set up in one particularly advantageous configuration of the invention, if permission confirmation is not identified and rejection is not identified, to cause withdrawal of the output of the request notification (at the earliest) after the time and/or distance interval has passed only when the same relevant event has not been identified using a camera-based detection system before the time or distance interval has passed.
Waiting for a predefined time and/or distance interval after reaching the map-based relevant location is therefore advantageous since identification of the relevant location using a camera-based detection system often takes place only very late on account of the evaluation of camera data, under certain circumstances even so late that output of the request notification on the basis of the camera-based determined relevant location is carried out only after the actual location of the relevant event. If the display of the (first) request notification were already withdrawn at the map-based determined location of the relevant event, the display would be activated again a short time later since the relevant event has now been identified by the camera-based determination unit. In principle, the display of the request notification, which is activated on the basis of the camera-based determination of the relevant location, can remain activated until there is a permission confirmation or rejection by the driver or until this relevant event is canceled by a new event or a new request notification is intended to be displayed for an upcoming new event.
The longitudinally guiding driver assistance system according to the invention can be used for various types of support for the driver during longitudinal guidance.
The longitudinally guiding driver assistance system may therefore be in the form of a speed restriction system, for example, in which a maximum permissible limit speed can be predefined and the functional unit is set up to prevent the predefined or set maximum permissible speed from being exceeded by accordingly controlling the drive. If an upcoming event which results in a change in the maximum permissible maximum speed is now identified on the basis of map-based identification, the functional unit may be set up to then cause output of the request notification to permit automatic adjustment of the currently predefined maximum permissible maximum speed to a new maximum permissible maximum speed at a defined time before the upcoming event is reached, that is to say in a predictive manner. If the driver confirms the permission for the automatic adjustment of the maximum permissible maximum speed by means of a corresponding action, the functional unit then causes a corresponding adjustment. Depending on the direction in which the maximum speed has been adjusted, a higher speed than before or only a lower speed than before can then be permitted. If, before the maximum speed is adjusted for example, a speed was requested which was previously not permitted on account of the original maximum permitted maximum speed, the functional unit can now permit an accordingly higher speed, at least when the request is below the new maximum permitted maximum speed. If the originally permitted maximum speed was greater than the newly permitted maximum speed, the functional unit may cause a corresponding reduction in the actual speed, ideally in such a manner that—if still possible—the new maximum permitted maximum speed is no longer exceeded at the location of the relevant event. If such an adjustment is no longer possible since the location has already been passed, it is possible to brake to the new maximum speed according to a predefined deceleration strategy.
In an alternative embodiment, the longitudinally guiding driver assistance system may also be in the form of a speed regulation system (with or without a distance function), the maximum permissible maximum speed being able to be used as the desired speed. In this case, however, it is possible to predefine a restriction such that the maximum permissible maximum speed can be (temporarily) used as the new desired speed only when it is lower than a maximum permissible desired speed predefined by the driver. In accordance with this restriction, the functional unit can be designed to only cause the output of a request notification to permit a change in the maximum permissible maximum speed (in this embodiment: desired speed) and, upon confirmation, to cause an adjustment of the speed regulation taking into account this new desired speed when the new maximum permissible maximum speed is lower than the maximum desired speed predefined by the driver. It is therefore possible to ensure that the decision on the maximum permissible speed which the driver wishes to achieve during free travel still remains with the driver.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.